Hand Muscular Strength Test

Hand Muscular Strength Tests are isometric tests that evaluate the strength of the hand and forearm muscles and there function, they are carried out in the extreme range, and if positive, in the neutral range. These isometric tests must include the interossei and lumbricals.

Pain with any of these tests requires a more thorough examination of the individual muscles. The clinician should be able to extrapolate hand placements for these strength tests by noting the anatomy of these muscles.

The muscles controlling wrist extension, wrist flexion, radial deviation, and ulnar deviation are tested first.

See Also: Hand Anatomy

Wrist Muscular strength test

FCR/FCU:

During the testing of these muscles, substitution by the finger flexors should be avoided by not allowing the patient to make a fist. The clinician applies the resistive force into extension and radial deviation for the FCU, and extension and ulnar deviation for the FCR.

ECRL/ECRB:

Any action of the EDC should be ruled out by having the patient make a fist while extending the wrist. The clinician applies the resistive force on the dorsum of the second and third metacarpals, with the force directed into flexion and ulnar deviation.

Extensor Carpi Ulnaris:

The ECU is tested by having the patient make a fist in wrist extension, while the clinician applies resistance on the ulnar dorsum of hand, with the force directed into flexion and radial deviation.

See Also: Wrist Anatomy

Hand Strength Tests

Thumb Muscles Strength Test

APL/APB:

The forearm is positioned midway between pronation and supination, or in maximal supination. The MCP and IP joints are positioned in flexion. The muscles are tested with anterior (palmar) abduction of the thumb in the frontal plane for the longus and in the sagittal plane for the brevis.

Opponens Pollicis:

The forearm is positioned in supination and the posterior (dorsal) aspect of the hand rests on the table. The patient is asked to touch the finger pads of the thumb and little finger together. Using one hand, the clinician stabilizes the first and fifth metacarpals and the palm of the hand. With the other hand, the clinician applies a force to the distal end of the first metacarpal in the opposite direction of opposition (retroposition).

FPL/FPB:

The forearm is positioned in supination and supported by the table, and the hand is positioned so that the posterior (dorsal) aspect rests on the table. The thumb is adducted. The longus is tested by resistance applied to the distal phalanx, whereas both heads of the brevis are tested by resistance applied to the proximal phalanx.

Adductor Pollicis:

This muscle is tested by having the patient hold a piece of paper between the thumb and radial aspect of
the index finger,s proximal phalanx while the clinician attempts to remove it. If weak or nonfunctioning, the IP joint of the thumb flexes during this maneuver due to substitution by the FDP (Froment sign).

Extensor Pollicis Longus/EPB:

Both of these muscles can be tested with the patient’s hand flat on the table, palm down, and asking the patient to lift only the thumb off the table. To test each individually, resistance is applied to the posterior (dorsal) aspect of the distal phalanx for the EPL while stabilizing the proximal phalanx and metacarpal and to the posterior (dorsal) aspect of the proximal phalanx for the EPB while stabilizing the first metacarpal.

Intrinsics Muscles Tests

Lumbricals:

The four lumbricals are tested by applying resistance to the posterior (dorsal) surface of the middle and distal phalanges, while stabilizing under the proximal phalanx of the finger being tested. The anterior (palmar) and posterior (dorsal) interossei act with the lumbricals to achieve MCP flexion coupled with PIP and DIP extension.

Anterior (palmar) Interossei:

The three anterior (palmar) interossei adduct the second, fourth, and fifth fingers to midline. Resistance is applied by the clinician to the radial aspect of the distal end of the proximal phalanx of the second, fourth, and fifth fingers, after first stabilizing the hand and fingers not being tested.

Posterior (dorsal) Interossei/Abductor digiti minimi (ADM):

The four posterior (dorsal) interossei abduct the second, third, and fourth fingers from midline. The ADM abducts the fifth finger from midline. The intrinsic muscles strength are tested in the frontal plane to avoid substitution by the extrinsic flexors and extensors. Resistance is applied by the clinician to the ulnar aspect of the distal end of the proximal phalanx of each of the four fingers, after first stabilizing the hand and fingers not being tested.

Fingers Strength Test

Flexor Digitorum Profundus:

This muscle is tested with DIP flexion of each digit, while the MCP and PIP are stabilized in extension and wrist neutral. Due to the variability of nerve innervation for this muscle group, each of the fingers can be tested to determine whether a peripheral nerve lesion is present. The index finger is served by the anterior interosseous nerve, the middle finger by the main branch of the median nerve, and the ring and little finger by the ulnar nerve.

Flexor Digitorum Superficialis:

There is normally one muscle tendon unit for each finger; however, an absent flexor digitorum superficialis to the little finger is common. The clinician should only allow the finger to be tested to flex by firmly blocking all joints of the nontested fingers, with the wrist in neutral.

ED/Extensor Indicis Proprius:

There is only one muscle belly for this four-tendon unit. These three muscles are the sole MCP joint extensors. With the wrist in neutral, the strength is tested with the metacarpals in extension and the PIP/DIP flexed. The extensor indicis proprius can be isolated by positioning the index finger and hand in the “number one” position—the index finger in extension with other fingers clenched in a fist. The EDM muscle is tested with resistance of little finger extension with the other fingers maintained in a fist.

To isolate intrinsic muscle function, the patient is asked to actively extend the MCP joint and then to attempt to actively extend the PIP joint. Because the ED, EI, and EDM tendons are “anchored” at the MCP joint by active extension, only the intrinsic muscles can now extend the PIP joint. To test the terminal extensor tendon function, the clinician stabilizes the middle phalanx and asks the patient to extend the DIP joint.

Flexor Digiti Minimi:

The forearm is positioned in supination and the posterior (dorsal) aspect of the hand rests on the table. The clinician stabilizes the fifth metacarpal and the palm with one hand, and then applies resistance to the anterior (palmar) surface of the proximal phalanx of the fifth digit with the other hand.

Opponens Digiti Minimi:

The forearm is positioned in supination and the posterior (dorsal) aspect of the hand rests on the table. The patient is asked to touch the finger pads of the thumb and little finger together. Using one hand, the clinician stabilizes the first and fifth metacarpals and palm of the hand. With the other hand, the clinician applies a force to the distal end of the fifth metacarpal in the opposite direction of opposition (retroposition)

References

1. Chase RA: Anatomy and kinesiology of the hand. In: Hunter DM, Mackin E, Callaghan M, eds. Rehabilitation of the Hand. St Louis, MO: Mosby, 1995.
2. Wadsworth C: Wrist and hand. In: Wadsworth C, ed. Current Concepts of Orthopedic Physical Therapy – Home Study Course. La Crosse, WI: Orthopaedic Section, APTA, 2001.
3. Schreuders, Ton. (2004). Muscle Strength Measurements of the Hand. Archives of Internal Medicine – ARCH INTERN MED. Link